This invention relates to a circuit arrangement for generating a supply voltage in the form of a dc voltage which is high relative to a reference voltage. The circuit comprises a chain of diode arrangements which are connected in series with one end of said clain delivering the high dc voltage, the junctions of the diode arrangements each being connected to a respective capacitor. The other terminals of the capaciters are connected alternately to another one of two pulse outputs of a pulse generator, non-overlapping pulses being generated at the pulse outputs.
A circuit arrangement of this kind is known from the publication "IEEE Journal of Solid-State Circuits", Vol. SC-11, No. 3, June 1976, pp. 374 to 378. The high voltage thus generated serves to power given circuit elements or circuit sections, for example, the so-called EEPROMs in a digital circuit arrangement. In the known circuit arrangement the pulse generator comprises an oscillator which controls the two pulse outputs of the pulse generator via two series-connected inverters. Overlapping of the pulses at the two pulse outputs is prevented by appropriate proportioning and the amplitude of the pulses generated at these outputs is inherently lower than the supply voltage.
Digital circuit arrangements are often powered by way of a comparatively high-ohmic ac voltage, via a bridge rectifier. An example of such an arrangement is the so-called contactless chip card where an integrated semiconductor circuit is inserted in a data carrier resembling a credit card, the data exchange and the powering of the circuit being realised via a single coil by way of an ac voltage of high frequency induced therein. This gives rise to some problems which necessitate special steps. Due to the construction and the operation of such a chip card in conjunction with an appropriate reading device and a coil contained therein, the coupling between the two coils is not very tight, so that the rectified supply voltage derived from the ac voltage may be loaded only to a small extent. Furthermore, the limited size of the coil makes the generation of comparatively high supply voltages difficult or almost impossible. Moreover, the value of the ac voltage and hence that of the dc voltage derived therefrom is not very constant and must be stabilized by way of special steps. The derived dc voltage, moreover, is lower than the amplitude of the ac voltage by an amount corresponding to the forward voltages of the bridge rectifier. Thus, when the described circuit arrangement is to be used in such a device, a comparatively large number of stages will be required in order to reach the necessary level of the high dc voltage in a reliable manner.